Foolish, stirring up endless dispute (6)
I believe the answer is:
stupid
'foolish' is the definition.
(similar in meaning)
'stirring up endless dispute' is the wordplay.
'stirring up' indicates an anagram.
'endless' means to remove the last letter.
'dispute' with its last letter taken off is 'disput'.
'disput' is an anagram of 'STUPID'.
(Other definitions for stupid that I've seen before include "Dull" , "Ignorant" , "Gormless" , "Senseless" , "Barmy" .)